2219铝合金搅拌摩擦焊缝Al2Cu相聚集行为特征分析

对2219C10S状态铝合金进行搅拌摩擦焊接试验,发现焊缝中存在聚集物的异常聚集现象,聚集相在X光检测中显示为亮白色聚集物,主要形态分为团块状、线状和指状三种,聚集相处焊缝的力学性能与无聚集相焊缝的力学性能基本相同。各形态聚集相的分布位置受搅拌头焊接影响区域的不同而不同,团块状聚集相主要存在于焊核中心或偏焊缝上表面位置处,线状和指状聚集相主要存在于焊核中心或偏焊缝根部位置处。对异常聚集相进行能谱分析知,聚集相主要组成元素为Al和Cu,原子百分比近似为2∶1,确定聚集相主要成分为Al2Cu。对聚集相的成因进行分析认为,聚集相的产生主要受搅拌摩擦焊接热输入及搅拌头机械搅拌作用的影响,在焊接过程中,塑态软化金属中的Al2Cu在填补搅拌针后方空腔的过程中出现了聚集行为,随着塑态金属的凝固,聚集行为开始变得缓慢并结束。

Analysis of Al2Cu Aggregation Behavior Characteristics in 2219 Aluminum Alloy Friction Stir Welding Seam

The friction stir welding test was performed on the 2219 C10 S aluminum alloy. It was found that there was abnormal aggregation of aggregates in the weld. The aggregated phase was shown as bright white aggregates on X-ray inspection. The main forms were divided into clumps,lines and fingers,and the mechanical properties of the welds in the aggregate phase were basically the same as those of the welds without the aggregate phase. The distribution position of each form of aggregated phase is different depending on the area affected by the welding of the mixing head. The agglomerate aggregate phase mainly existed at the center of the weld or the upper surface of the weld,and the linear and finger-like aggregates mainly existed in the weld center or the position of the weld root. The energy spectrum analysis of the abnormal aggregate phase shows that the main constituent elements of the aggregate phase are Al and Cu,and the atomic percentage is approximately 2∶1. It is determined that the main component of the aggregate phase is Al2Cu. Analyzing the causes of the aggregate phase,the generation of aggregate phase is mainly affected by the welding heat input and the mechanical agitation of the mixing head. During the welding process,Al2Cu in the plastic softened metal shows aggregation behavior in the process of filling the cavity behind the stirring needle,solidification with metal,aggregation behavior begins to slow down and ends.